Propulsion and braking control system



Dec. 26, 1944. c. M, HINES 2,366,029

PROPULSION AND BRAKING CONTROL SYSTEM Filed Deo. 3l, 1942 3 Sheets-Sheetl 255%@ 1417 Z142 es@ -F -A E I I z g c:

CoA5T|NG EMERGENCY NoN-OPER. 125 Z@5b z ACCELERATT; BQAMN" 10 126 6????@W6 121\ m im Il l Sbv 51c\ 101 '/d' iode 2057 J 77 l-B- /155 J I 16e 2*2 4 l z E] I l A J 155 i i J 128 '5g 5 uw 166 .nmnffm 'uu-15x61. i l Jl A J M165 f' "50? J 1]]157/ ,mj 15?/ i l l m61 161 51g 51j` 51rd 511110Q@ lNvEN'roR M CLAUDE M. HINES WQ/@m ATTORNEY Dec. 26, 1944. C; MHlNES 2,366,029

PROPULSION AND BRAKING CONTROL SYSTEM Filed Dec. 3l, 1942 3 Sheets-Sheet2 Zib INVENTOR 5 CLAUDE M. HINES a BY @im ATTORN EY Dec. 26, 1944. c. M.HINEs PROPULSION AND BRAKING CONTROL SYSTEM Filed Dec. 3l, 1942 3Sheets-Sheet 3 INVNTOR CLAUDE M. H1 NES ATTORNEY Atric propulsionPatented Dec. 26, 1944 UNITED STATES PATENT OFFICE PROPULSION ANDBRAKING CONTROL SYSTEM Application December 31, 1942, Serial No. 470,806

36 Claims.

This invention relates to propulsion and braking control systems forvehicles, such as railway cars and trains, and has particular relationto electric propulsion and braking systems having a plurality of typesof braking devices, for example, a dynamic brake utilizing thepropulsion motors of the vehicle, a magnetic track brake, and a frictionbrake of the spring-applied electrically-released type.

Street railway cars .or cars in subway service are commonly providedwith braking systems of the multiple brake type, known as the PCC type,in which the propulsion motors function as dynamic brakes to provide acertain maximum degree of braking, in which magnetic track brakessupplement the degree of braking an'd in which friction brakesassociated with the car wheels are employed for providing additionalbraking and for parking. The parking brakes commonly employed are of theuid pressure controlled type necessitating the usual brake cylinders,piping, and fluid compressors for charging reservoirs.

It is an object of my present invention to provide a novel brakingsystem for traction railway vehicbs of the multiple brake type,characterized in that all of the various brake devices employed,including the parking brakes, are of the electrically controlled typeso-as to obviate the necessity for fluid compressors, piping, and brakecylinders.

It is 'another object of my invention to provide a propulsion andbrakingV system wherein noval control apparatus is provided forcontrolling the propulsion motors both during propulsion and duringdynamic braking.

It is another object of my vinvention to provide novel vehiclepropulsion motor control ap.. paratus of the type disclosed in PatentNo. 2,120,956 to J. F. Tritle.

The above objects, and other objects of my invention which will be madeapparent hereinafter, are attained in an illustrative embodiment of myinvention shown in the accompanying drawings, wherein Figures 1A and 1B,taken together, constitute a simplified diagrammatic view of an allelecand multiple brake control system, f

Figure 2 is a diagrammatic plan view of the reversible stepping relayemployed in the motor control system shown in Figs. 1A and 1B,

Figure 3 is a view, taken on the line 3--3 oi' Figure 2, showing infurther detail the structure of the stepping relay of Fig. 2, and

Figure 4 is a view, partly in section, showing details of thespring-applied electrically released friction brakes employed inconnection with the propulsion motors iin the system of Figs. 1A and 1B.

The electric propulsion and braking system shown in Figs. 1A and 1B isillustratively applied to a single car having two wheel trucks, one ateach end of the car. The wheel trucks shown are of the four-wheel typehaving two wheel and axle assemblies, each assembly comprising twowheels fixed at opposite ends of a connecting axle. The respective wheeland axle assemblies are designated II a, IIb, IIc and Ild in thedrawings. Only one wheel of each assembly is visible in the drawings.Each wheel and axle assembly is coupled to the shaft I3 of correspondingpropulsion motor I2 (see Fig. 4) through a suitable drive mechanism notshown.

For convenience of identification, the motor for each wheel and axleassembly employs the suffix letter a, b, c, and d oI.' the correspondingwheel and axle assembly to designate the armature winding and the seriesfield winding of the corresponding motor. Thus, in Figure 1B thearmature windings of the four motors are designated I2a, IZb, I2c, andI2d respectively and the series field windings are designated I la, IIb,I4c, and Md, respectively.

The propulsion motors I2 are arranged to be connected for operation asdynamic brakes by means of control apparatus hereinafter to bevdescribed.

Associated with each propulsion motor is asocalled parking brake of thespring-applied solenoid-released type, shown in Figure 4 anddiagrammaticaliy indicated in Figs. 1A and 1B. Briefly, thespring-applied solenoid-released brake associated with each of themotors comprises a brake drum I5 fixed on an extension of the armatureshaft I3 of the motor and two brake shoes I5 located respectively ondiametrically opposite sides of the brake drum forL engaging the brakedrum. The brake shoes Itare respectively carried by curved levers Il,each of which is pivoted at the lower end thereof on an extension I8 ofthe frame of the motor and arranged, in familiar manner, to be urgedtoward each other by a coll spring I9 to effect application of the shoesI 6 to the drum. The spring I9 is compressed and the levers II movedapart to disengage the shoes from the brake drum by a compound solenoiddevice ZI The solenoid device 2l comprises a main or release solenoid2Ia and an auxiliary or releasemaintaining solenoid 2lb, arranged incoaxial relation in a manner to individually exert an upward force on acommon plunger 22 which is connected at its upper end through a slot andpin connection to a bell crank lever 23. The bell crank lever 23 is soconnected to the levers I1 carrying the brake s hoes to effectcompression of the spring I9 and separation of the levers I1 when theplunger 22 is raised. i

The main solenoid 2 Ia is larger than the auxiliary solenoid 2lb and iscapable of exerting a greater force than solenoid 2lb on the plunger 22in order to initially overcome the spring I9 to effect the release ofthe brake shoes I8 from the brake drum I5. The auxiliary solenoid 2lb isso designed that it is capable of exerting suillcient force on theplunger 22 to hold the spring I9 in compressed condition to maintain thebrake shoes released from the brake drum after the brake shoes have beenreleased by action of the main solenoid 2Ia.

The solenoids 2Ia and 2lb are controlled in such a manner, hereinafterdesibed in detail, that after the brake shoes have been released by themain solenoid 2Ia, the auxiliary solenoid 2Ib is energized to hold thebrakes released and the main solenoids 2 Ia is then deenergized. It isthus possible to minimize the amount of electrical current or energyrequired to maintain the brake shoes in release position since auxiliarysolenoids 2lb requires less current than solenoid 2Ia.

Each of the wheel trucks also carries two magnetic track brake devices25, located respectively on opposite sides of the truck, for engagementwith opposite rails of the tracks. The track brake devices 25 arenormally suspended above and out of contact with the track rails byhelical springs and are actuated by magnetic attraction into engagementwith the track rails in response to energization of the magnetic winding25a thereof.

The magnetic track brake devices 25 and the propulsion motors I2 arecontrolled by means of a combination propulsion and braking controller21, diagrammatically indicated in Figure 1A. Controller 21 is of the camoperated contactor type having a rotary shaft to which an operatingrhandle 28 is removably attached. Handle 28 is arranged in familiarmanner, as diagrammatically shown, to close and open a deadman switch 28in response to the application and release respectively of downwardpressure on the handle.

As diagrammatically shown, the controller 21 comprises a plurality ofswitches respectively designated 30a, 30h, 30C, 38d, 30e, 30j, 30g, 30h,311i, 307, 30k, 301, 30m and Inn. The cams for operating the respectiveswitches are diagrammatically indicated in a horizontal line oppositethe corresponding switch and are respectively designated 3l a to 3| n.

As diagrammatically shown, the controller handle 28 has a normalposition, designated Coasting position, and is shiftable to oppositesides of the Coasting position into a braking zone and an acceleratingzone respectively.

As `the controller handle 28 is shifted away from the coasting positioninto the braking zone it passes successively through six service brakingpositions designated I to 5 respectively, then into a positiondesignated Emergency position. and nally into a Non-operative position.The controller handle 23 is so arranged that it may Ibe removed only inthe non-operative position thereof. Various expedients are known forpreventing the removal of the controller handle except in apredetermined operating position thereof and accordingly such structureis not illustrated.

When the controller handle 28 is shifted into the accelerating zone, itpasses successively thiough six positions, designated respectively I toAs will be explained more fully hereinafter, the degree of brakingeiIected increases progressively as the degree of displacement of thecontroller handle 28 out of Coastlng position into the braking zoneincreases. Similarly, the rate of acceleration increases progressivelyas the displacement oi the controller handle 28 out of Coasting positioninto the accelerating zone increases.

While I have shown only six service braking positions and sixaccelerating positions, any desired number of positions may be employed.

The controller switches 30a to 3Iln are opened and closed in certainpredetermined positions of the controller shaft and handle 28. It willbe understood that a controller switch is closed only in a positioncovered by the corresponding cam 30a to 30u.

Associated with and operated by rotation of the operating shaft of thecontroller is a rheostat 32. The rheostat 32 preferably comprises aresistor 32a having progressively spaced tap connections which areconnected to successive segments of a non-rotative commutator (notshown). Assoelated with the commutator is a brush or movable contactarm, indicated diagrammatically at 33. The brush device 33 is fixed onthe operating shaft of the controller 21 and is rotated incorrespondence with the rotary movement thereof. The arrangement of theresistance 32a of the rheostat 32 is such that the brush device 33 isdisplaceable in opposite directions from a neutral positioncorresponding to the Coasting position of the controller handle 28 toprogressively increase the resistance between the point of contact ofthe brush with the commutator and the neutral position thereof in themanner more fully explained hereinafter.

The controller 21 functions together with control apparatus hereinafterto be described and its operation will be fully explained hereafter inconnection with an assumed operation.

The control apparatus associated with the controller 21 comprises aplurality of motor control resistors 38, 31, and 38; a rheostat 38including a resistor 4I, operating mechanism in the form of a reversiblestepping relay 42, and limit switches 43. 44, 45, and a; two transfer orcontrol relays 48 and 41, respectively, for controlling the direction ofoperation of the stepping relay 42 and resistors 31 and 38; a pair ofcurrent limit or current regulating relays 48 and 48 for controlling theoperation of the stepping relay 42; two resistors'l and 52 included inthe motor control circuit and arranged in a manner to control theoperation of the current limit relays 48 and 43: motor field shuntingapparatus including a shunting relay 54, two resistors 54a and 54h,respectively, and two reactors 55a and 55h; a cushioning relay 58; abrake control relay 51; an emergency relay 58; and a lock-out relay 59.

Associated with the controller 21 for the purpose of controlling themagnet; windings 25a of the magnetic track brake devices are two relays82 and 63 and two resistors 84 and 65.

An additional relay 68 is also provided for each wheel and axle assemblyfor the purpose of controlling the main and auxiliary solenoids 2 la and2lb of the spring-applied brake device associated therewith.

The control apparatus further comprises an emergency wire comprising twowires 58a and 68h extending from end to end of the car and connected toeach other at one end through a loop connector 63. When the car isemployed in a train, the loop conductor is only on the end car, thesections of the wires 88a and 88h on the car being suitably connectedbetween cars. Interposed in one of the wires, such as the wire 68a is aconductors switch 1l which is normally closed and opened only inresponse to the application of pressure thereto.

The deadman switch 29 associated with the controller 21 and theconductors switch 1| are employed in a manner more fully describedhereinafter to control the energization and deenergization of theemergency wire 68h which in turn controls the emergency relay 58.

Considering the parts of the control apparatus in greater detail, thestepping relay 42 (see Figs. 2 and 3) comprises a rotary armature oroperating shaft suitably journaled in spaced supports 16. Fixed on theshaft 15 in spaced coaxial relation are two ratchet wheels 11 and 18respectively.

Associated with lthe ratchet wheel 11 of the stepping relay is anoperating device comprising a magnetic core 19, an electro-magneticWinding 8Ia on the core, and a pivoted armature 82,' Associated with theratchet wheel 18 is a similar operating device comprising a magneticcore 19, an electromagnetic winding 8| b on the core, and a pivotedarmature 82. Each armature 82 is normally biased away from its core 19by a spring 83, attached at one end to the armature and at the other endto a fixed support or base 84, and is attracted to the core in responseto energization of the corresponding winding 8|a or 8|b.

Connected in series relation with the windings 8|a and 8| b andassociated with the corresponding armature 82 is a switch 85a and 85h,respectively of the telephone type having two contact fingers normallybiased into contact with each other. One of the contact fingers of eachswitch is bent by the armature when attracted to the core 19, to causeseparation of the contact lingers of the switch. f

The switches 85a and 85h operate in Well known manner to control thecorresponding winding 81a and 8|b so as to cause automatic and repeateddeenergization and energization of the winding and the consequentrepeated movement of the corresponding armature 82 towardand away fromcore 19.

Each of the armatures 82 has a hook shaped pawl 88 attached theretowhichextends into cooperative relation with the corresponding ratchet wheel11 or 18 and which is effective to advance the ratchet wheel one or moretooth distances each time the movement of the armature toward the core19 is effected in response to energization to the corresponding winding8| a or 8|b.

The ratchet wheels 11 and 19 have their teeth inclined respectively inopposite directions so that the alternate energization anddeenergization of the magnet winding 8|a causes rotational movement ofthe operating shaft 15 in one direction and the alternate energizationand deenergization of the magnet winding 8 Ib causes rotational movementof the shaft 15 in the opposite direction.

In order to hold the ratchet wheels 11 and 18 against movement as thepawls 86 are restored backwardlyin response to the deenergization of thecorresponding winding 8 la or 8 Ib, each of the armatures 82 has aflexible leaf spring 88 secured thereto which frictionally engage theteeth of the l ratchet wheel associated with the other operating device.

As thus far described the reversible stepping relay is generally similarto the relay device disclosed in Patent 1,932,020 issued to B. Lazichand is in itself not my invention.

The rheostat 39 comprises a brush holder 9| fixed on the shaft 15carrying in insulated relation therein a contact or brush 92 forengaging a commutator 93 that is non-rotatively supported in coaxialrelation to the shaft 15, as by a support 94. The commutator 93 has aplurality of commutator segments to each of which a separate wire,indicated by the group of wires 95, is connected. The group of wires 95are contained in a cable 96 that extends through a tubular shaft 91carrying the commutator 93 and secured in the support 94. The wires 95are connected to progressively spaced points of the resistor 4|. It willthus be apparent that as the brush 92 rotates with respect to thecommutator 93 it progressively increases or decreases the amount of theresistorv 4| in a circuit including the resistor 4|.

A plurality of limit switches 43, 44, 45 and 45A are associated with theshaft 15 and are operated by contact arms 98, 99, and |00 fixed on theshaft.

The limit switches 43 and 44 are identical, each comprising threeflexible Contact fingers a, b, c, supported in a row in an insulatingmember d, in a given plane. The contact finger b has an inherent bias inthe direction of the contact finger a and normally engages the contactfinger a. The contact arm 98 engages an extension of the contact fingerb when the shaft 15 reaches on extremity of rotary movement thereof andbends it out of contact with the finger a and into engagement with thecontact finger c. In a similar manner, when Vthe rotary shaft 15 reachesthe opposite extremity of rotary movement thereof, the contact arm 98engages the contact finger b of the limit switch 44 and bends it out ofcontact with r the contact nger a and into engagement with contactfinger c. f

Limit switch 45 has two flexible contact fingers a and b supported in aninsulating base d. The

contact ringer b is normally biased to a position out of engagement withthe contact finger a and is bent into contact with the contact finger awhen the contact arm 99 engages the contact finger b at the time therotary shaft 15 reaches the same extremity of rotary movement thereof atwhich it operates the limit switch 44.

Limit switch 45A has two contact fingers a and b supported in aninsulating base d and normally biased into engagement with each other.Contact arml is arranged to engage an extension of contact linger b toseparate it from finger a where the brush 92 reaches the same extremityof movement at which limit switches 44 and 45 are operated by theirrespective arms 98 and 99.

Energization of one or the other lof the magnet windings 8|a or 8|b ofthe operating mechanism of the rheostat 39 is selectively effected underthe Joint control of the two relays 46 and 41. The relays 46 and 41 arestandard relays having a slow drop-out characteristic, the reason forthe slow drop-out characteristic being made apparent hereinafter. Therelays 46 and 41 comprise the usual magnetic core having a magnetwinding w associated therewith and an armature which is actuated to apicked-up position from a normally dropped-out position to which it isbiased by a spring means or by gravity, in response to the energizationof the winding w. The two relays 46 and v41 are identical inconstruction and each has a plurality of contact member or switcheswhich are operated by the armature of the relay. Thus, each of therelays 46 and 41 has three front contacts a, b, and c which are actuatedfrom an open to a closed position in response to the pick-up of thearmature of the relays. Each o1' the relays 46 and 41 also f. Thetransfer contacts d, e, and f occupy alternatively one or the other oftwo circuit-closing positions depending upon whether the armature of therelay is in its dropped-out or its pickedup position.

Each of the current limit relays 48 and 48 comprises the usual magneticcore structure having a winding w associated therewith and an amaturefor actuating a plurality of contacts including one front contact a andtwo back contacts and c respectively.

The windings w of the two relays 48 and 49 are not identical, thewinding of the relay 48 being designed to cause pick-up of the contactsof relay 48 in response to energization by a current lower than thatrequired to cause pick-up of the contacts of the relay 49.

As will be explained more fully hereinafter, the windings w of therelays 48 and 49, the resistor '32a of the rheostat 32 associated withthe controller 21 and resistor 5| are connected in series relationacross the resistor 52, which is included in the motoring or dynamicbraking circuit of the motors. The relays 49 and 49 are thus responsiveto the motoring and dynamic braking current.

The field shunting relay 54 is a standard relay of the neutral typehaving the usual magnetic core with which is associated a magnet windingw and an armature for actuating a plurality of contacts a, b, c, d, ande. The contacts a, b, and c of the relay 54 are front contacts, that is,they are closed only when the armature of the relay is picked-up. Thecontacts d and e of the relay 54 are back contacts, that is, they areclosed only when the armature of the relay is in its droppedoutposition.

The contacts of the relay 54 are shown in their picked-up positionbecause a circuit hereinafter described, is established to cause pick-upof the relay 54 when the controller handle 28 is in its Coastingposition, as it is assumed to be.

The contact b of the relay 54 is effective in its picked-up or closedposition to establish a shunt circuit including the series-connectedresistor 54a and the reactor 55a around the motor field W'ndings Hc andHd. The contact c of relay 54 is effective in its picked-up or closedposition to establish a shunting circuit including the seriesconnectedresistor 54h and the reactor 55h around the motor field windings |4a andI4b. These shunting circuits are readily apparent in Figure 1B of thedrawings and need no further description.

The function of the contacts a, d, and e of the relay 54 will be madeapparent hereinafter.

The cushioning relay 55 is a standard relay or the neutral type havingthe usual magnetic core, with which a magnet winding w is associated,and an armature normally biased to a dropped-out position by a spring orgravity and actuated to a picked-up position in response to energizationof the winding w. The relay 56 has ilve front contacts a, b, c, d and ewhich are actuated from their dropped-out or open positions to theirpicked-up or closed positions in response to the pick-up of the armatureof the relay.

The contact c of the cushioning relay 58 is effective in its picked-upor closed position to establish a short circuit connection around theresistor 36 which is included in the motoring circuit. The function ofthe other contacts of the relay 56 will be made apparent hereinafter.

'I'he brake control relay 51 is a standard neutral relay having theusual magnetic core, with has three transfer contacts designated d, e,and4 which a winding w is associated, and an armature actuated from adropped-out to a picked-up position in response to energization of theWinding w, which armature operates a plurality of contacts a, b, and c.The contact a of the relay 51 is a front contact and the contacts b andc are transfer contacts which occupy alternative circuit-closingposition in the dropped-out and picked-up positions thereof,respectively.

The relay 51 functions, in a manner hereinafter desa'ibed, whenpicked-up to establish a circuit for supplying propulsion current to themotors and when dropped-out for establishing a dynetic winding wassociated therewith, effective when energized to cause pick-up of anarmature which actuates a plurality of contacts a, b, c, d and e. Thecontacts a, b, and c of the relay 58 are front contacts and the contactsc and d of the relay 58 are back contacts.

The lock-out relay 59 comprises the usual magnetic core and two separatewindings wl and w2, either of which is effective when energized to causepick-up or to maintain picked-up the armature of the relay, which inturn actuates a single front contact a. Relay 59 also has a slow dropoutcharacteristic.

'I'he windings of the various relays thus far described are energized bycurrent supplied from a suitable source oi' direct-current, such as astorage battery or a direct-current generator. For convenience, thepositive terminal of the source of direct-current is indicated by thedesignation B+ and the negative terminal is indicated by the designationB.

In Figure 1A, a wire IDI, hereinafter referred to as the positive buswire, is connected through a normally closed manually operated switch|02 to the positive terminal B+ of the source of current and, unlessotherwise indicated, circuits will be hereinafter traced beginning withthe positive bus wire IOI for simplicity.

The lock-out relay 59 functions in the manner hereinafter to bedescribed to control the relays 6B, which in turn control the solenoids2la and 2lb of the spring-appied friction brake devices associated withthe motors.

The relays 52 and 63 are simple neutral relays, each having an operatingwinding w and a single contact a. The contact a of the relay 62 is atransfer contact while the contact a of the relay 63 is a front contact.

The winding w of the relay 92 is energized under the joint control ofcontact e of emergency relay 58 and of the switch 30u of the controller21. As will be seen in Figure 1A, controller switch 301i is closed inthe braking positions 4, 5, and 6 of the controller.

The winding w of the relay 63 is energized in response to the closure ofthe switch 30m of the controller 21, which as seen in Fig. 1A occurs inbraking positions 5 and 6 and the Emergency position of the controller,Winding w of relay 88 is also energized under the joint control of thecontroller switch 301 and contact d of the emergency relay 58 in allpositions of controller 21 except the non-operative position.

It will thus be apparent that as the handle 28 of the controller 21 isshifted out of the Coasting position thereof, both relays remaindeenerglzed through the initial three braking positions I, 2, and 9.Thereafter, as the displacement of the controller handle out of theCoasting position is further increased, the relays 62 and 63 aresuccessively picked-up and then relay 62 is droppedout.

With the relay'62 picked-up and the relay 63 dropped-out, a circuit isestablished for energizing the magnet windings 25a of all of themagnetic track brake devices 25, which circuit includes the tworesistors 64 and 65 in series relation therein. This circuit extendsfrom the positive bus wire I| by way of a branch wire |04, resistor 64,contact a of relay 62 in its picked-up position, a wire including theresistor 65, a wire |06 which is connected to a bus wire |01, then inparallel through all of the magnetic windings a of the magnetic trackbrake devices to the negative terminal B- of the source of current.

The magnet windings 25a are thus energized to a minimum degreesuflicient to cause frictional engagement of the magnetic track brakedevices with the track rails and the production of a corresponding lowdegree of braking effect.

With both the relays 62 and 63 picked up, a circuit is established forenergizing the magnet windings 25a of the magnetic brake devices, whichcircuit includes only the resistor 64. This circuit extends from thepositive bus wire I 0I by way of. the branch wire |04, resistor 64,contact a of relay 63, wire |06, bus wire |01, then in parallel throughthe magnet windings 25a, to the negative terminal B- of the source ofcurrent. With the resistor thus cut-out of the circuit, the currentenergizing the magnet winding 25a is correspondingly increased.

With only the relay 63 picked-up a circuit is established for energizingthe magnet windings 25a of the magnetic track brake devices fromwhichthe two resistors 64 and 65 are cut-out. This circuit extends fromthe positive bus wire |0| by way of the branch wire |04, contact a ofthe relay 62, contact a of the relay 63, wire |06 to the bus wire |01,and then in parallel through the track brake magnet windings 25a to thenegative terminal B- of the source of current.

As previously indicated, windingw of the relay 63 is also controlledjointly according to the position of the controller handle 28 and theposition of the emergency relay 58. Thus, in all positions of thecontroller 21, except non-operative position, contact d of the emergencyrelay 58 is effective in its dropped-out position to establish a circuitfor energizing the winding w of the relay 63, which circuit extends fromthe positive bus wire |0I, by way of a branch wire |09 including inseries relation therein the controller switch 30| and the back contact dof the emergency relay l56, and the Winding of the relay, to thenegative terminalB- of the source of current. The track brake windings25a are thus energized to a maximum degree whenever the emergency relaydropsout because relay 62 is restored simultaneously to its dropped-outposition, if not already droppedout, in response to the opening ofcontact e of emergency relay 5B. v

Each of the relaysI 66 is a slow-acting relay comprising a magnetic corehaving two separate windings wI and w2 associated therewith, a resilientflexible contact a which is biased normally into contact with astationary contact b, and an additional contact c effective whenactuated to a picked-up position to rst engage contact a and thenseparate it from contact b.

The contact a of each relay 66 is connected by a wire |09a to a bus wireIIO, the bus wire I|0 nected by a wire I I2 to one terminal of thewinding wl of the relay 66, the other terminal of which is connected tothe negative terminal B- of the source of current. A branch wire |f|3 ofthe wire Il! is connected to one terminal of the solenoid winding 2|a ofthe corresponding spring-applied brake device, the other terminal ofwhich is cony nected to the negative terminal B- of the source ofcurrent. The winding wl of the relay 66 and the solenoid 2Ia are thusconnected in parallel relation. i

In a similar mannerthe winding w2 of each relay 66 and the solenoid 2|bof the corresponding spring-applied brake devices are connected inparallel between the contact c of the relay 66 and the negative terminalB- of the source of current.

When the bus wire ||0 is first connected to the positive bus wire IOI, acircuit is established for energizing the winding wI of each relay 66and the solenoid 2Ia of the spring-applied brake device correspondingthereto. Due to the slow pick-up characteristic of the relays 66, aninterval of time elapses suilicient to insure the energization of thesolenoid 2 Ia in a manner to fully compress the coil spring I9 of thespring-applied brake device to fully release the brake shoes I6 from thebrake drum |5 before the contact c engages the contact a and disconnectsthe contact a from the contact b.

At the instant the contact c of each relay 66 rst engages the contact a,the two windings wl and w2 of the relay 66, as well as the two solenoids2|a and 2lb of the corresponding spring-applied brake device, are allsimultaneous/ly energized. Thereafter, when the contact C of the relay66 moves the contact a out of engagement with the contact b, the circuitfor energizing `the winding wI of the relay 66 and solenoid 2 Ia isinterrupted. By reason of the continued energization of the winding w2of the relay 66 over lthe self-holding contact c of the relay, theauxiliary solenoid 2lb of each spring-applied brake device isaccordingly maintained energized so as to maintain the brake shoes I6 intheir released position in opposition to the force of the spring I9.

The manner in which the lock-out relay 59 is controlled will beexplained in detail hereinafter, but it may be here stated that thearrangement is such that the relay 59 is maintained picked-up followingthe initiation of a brake application until such time as the degree ofdynamic braking effect reduces below acertain low degree as the carapproaches a stop. Thus, it will be seen that the spring-applied brakedevices are operated to exert a braking effect on the vehicle wheels byreason of the braking effect exerted on the armature shafts of thedriving motors only when the car is substantially stopped. Thespring-applied brakes thus function principally for the purpose ofparking.

OPERATION (a) coasting or starting condition Let it be assumed that thecar is at a standstill, or coasting, with the controller handle 28 inits Coasting position and depressed to close the deadman switch 29.

In such case, the winding w of emergency relay 58 is energized over acircuit extending from the positive bus wire |8| by way of a branch wire|2| including the controller switch 38a, manual switch |22 normallyclosed as shown, and the closed deadman switch 29 to the emergency wire88a, thence through the wire 88a including the closed conductors switch1| to the loop connector 69 at the end of the car to theemergency wire68h, thence by way of a branch wire |23 including in series relationtherein the winding w of emergency relay 58 to the negative terminal Bof the source of current.

In its picked-up position, the contact b of the emergency relay 58 isen'ective jointly with the controller switch 30C to effect energizationof the winding wl of the lock-out relay 59. This circuit extends fromthe positive bus wire by way of a branch wire |24 including in seriesrelation therein the controller switch 30e, the winding wl of thelock-out relay 59, and contact b of the emergency relay 58 to thenegative terminal B- of the source of current.

The contact a of the lock-out relay is accordingly actuated to itspicked-up or closed position. Accordingly, as previously described, thewinding wl of each of the relays 66 and the auxiliary solenoid 2|b ofthe spring-applied brake devices are energized so that the brake shoes Iare held released from the brake drum l5 on the motor shaft |3.

At the same time, the magnetic track brake relays 62 and 83 are bothdropped-out in the Coasting position of the controller 21 andconsequently the magnet windings 25a of the magnetic track brake devices25 are deenergized.

At the same time also, the brake control relay 51 is in its dropped-outposition establishing a dynamic braking circuit. 'I'his circuit may betraced from one terminal of the armature winding |2b of thecorresponding motor, by way of a wire |28, transfer contact b cfthebrake control relay 51 in its dropped-out position, a wire |21, windingw2 of the lock-out relay 59, a wire |28 including in series relationtherein the three resistors 52, 31, and 38, a branch wire |29, transfercontact f of the relay 41 in its dropped-out position, a wire |30,transfer contact f of the relay 48 in its dropped-out position, a wire|9I, a wire |32, resistor 4| of rheostat 39, brush 92 associated withthe commutator to which the resistor 4| is connected, a wire |33including a. flexible portion connected to the movable brush 92, a wire|34, transfer contact c of the brake control relay 51 in its dropped-outposition, a wire |35 to one terminal of the motor armature winding |2cwhere the circuit divides into two branches, one branch extending inseries relation through the armature windings |2c and |2d and fieldwindings |4a and |4b to the point o1' starting and the other branchextending in series relation through the motor field windings |4c and|4d, and the motor armature windings |2a and |2b to the point ofstarting.

Assuming that the car is at a standstill, and that the armatures of themotors are therefore not rotating, no current flows ln the dynamicbraking circuit. If the car were in motion, there would in any event bea negligible flow of dynamic braking current because of the fact thatthe motor field windings |4a and |4b are shunted through the contact cof the field shunting relay 54 and the motor eld windings |4c and |4dare shunted through the contact b of the field shunting relay 54.

It will be understood that the field shunting relay 54 is picked-up inthe Coasting position of the controller 21 by reason of the energizationoi the winding w of the relay under the control ol controller switch 30jwhich is closed in the Coesfing position of the controller. The circuitfor energizing the winding of the field shunting relay 54 extends fromthe positive bus wire by way of a wire |31 including in series relationtherein the controller switch 38f, a wire |38, winding w of the relay54, and thence to the negative terminal B of the source of current.

It will thus be seen that, with the controller handle 28 in the Coastingposition, all of the brakes are released.

(b) Propulsion Now let it be assumed that the operator desires to startthe car from a standstill. To do so, he shifts the controller handle 28into the accelerating zone an amount corresponding to the desired rateof acceleration, for example, to position 4.

Due to the fact that the switch 30h of the controller is closed in allaccelerating positions of the handle 28, a circuit is thus establishedfor energizing the winding w of the brake control relay 51. The contactsof relay 51 are thus actuated to their picked-up positions, wherein thepreviously traced dynamic braking circuit is interrupted and a motoringcircuit for supplying power current to the motors is established. Themotoring circuit for supplying power current from an external source tothe motors to propel the car may be traced from a trolley wire or thirdrail |4| connected to the source, (see Fig. 1A) then by way of a trolleypole or collector device |42, a wire |43, front contact a of the relay51, a wire |44 including in series relation therein the resistor 36 tothe point |45, whence the circuit divides into two parallel branches,one branch including the series-connected motor armature windings |211and |2b and field windings |4b and |4a, and the other branch includingthe seriesconnected motor field windings |4d and |4c and armaturewindings |2c and |2d, the two branch circuits rejoining at the point |46and continuing by way of the wire |41, transfer contact c of the relay51 in its picked-up position, wire |34, wire |93, brush 92 of therheostat 39, the entire resistoi 4|, wire |32, wire |3|, transfercontact f of the relay 45, wire |38, transfer contact I of the relay 41,wire |29, the wire |28 including in series relation the three resistors39, 31, and 52, winding wz of the lock-out relay 59, wire |21, transfercontact b of the brake control relay 51 in its picked-up position, andthen back to the external source of power through a ground connection at|48.

Current is accordingly supplied from the external source to the motorsto propel the car, the rate of acceleration depending upon the degree towhich the controller handle is displaced out of the Coasting positioninto the accelerating zone for reasons which will be subsequentlyexplained. Upon the rotation of the operating shaft of the controller 21in response to the movement of the controller handle into theaccelerating zone, the brush 33 of rheostat 32 is correspondinglyrotated to include a portion of the resistor 32a corresponding to thedisplacement of the controller handle out of Coasting position in thecircuit including the series-connected windings w of the current limitrelays 48 and 49 connected across the resistor 52 in the motoringcircuit. At the same time, the movement of the controller handle 28 outof the Coasting position causes the controller switch 30e to be openedand thereby remove the shunt connection around the resistor which isthus also included in the circuit of the windings of the relays 48 and49.

When the current in the motoring circuit rises above a. certain valuecorresponding to a certain rate of acceleration of the car motors, theeffective potential on the winding w of the current limit relay 48 iseffective to cause sufficient current to flow through the winding of therelay to cause pick-up of the contacts thereof,

The actuation of the back contact c of the relay 48 to its picked-up oropen position interrupts a holding circuit previously establishedthereby for maintaining the winding w of the field shunting relay 54energized, after the controller handle 28 is shifted out of the Coastingposition and the previously described energizing circuit, including thecontroller switch 30j, is correspondingly interrupted. The holdingcircuit just mentioned extends from the positive bus wire |8| by way ofa wire |5|, including closed controller switch 30k, contact c of therelay 48, a wire |52, front contact a of the relay 54, a wire |53, wire|38, winding w of the relay 54, and thence to the negative terminal B-of the source of current.

It will thus be seen that when the holding circuit for relay 54 isinterrupted at the contact c of the relay 48, relay 54 is restored toits dropped-out position.

In the dropped-out position of the relay 54, the

contacts b and c are effective to interrupt the motor field shuntingcircuits previously established thereby. The field current is thusinstantly increased and consequently a substantial increase in thepropulsion torque exerted by the motors takes place to effectacceleration of the car.

The restoration of the back contact d of the field shunting relay 54 toits dropped-out or closed position establishes a circuit for energizingthe winding w of the cushioning relay 56 and the contacts of thecushioning relay are accordingly actuated to their picked-up positions.The circuit for energizing the winding of the relay 56 extends from thepositive bus wire |0| by way of a branch wire |55 including in seriesrelation therein the controller switch 307' and the front contact a ofthe relay 48, contact d of the relay 54 in its dropped-out or closedposition, a wire |56, winding w of the cushioning relay 56, and then tothe negative terminal B- of the source of current.

The front contact a of the cushioning relay 56 is a self-holding contactwhich is effective in its picked-up or closed position to establish acircuit for maintaining the winding w of the relay 56 energizedthereafter as long as the controller handle 28 remains in theaccelerating zone. The

Aself-holding circuit for the winding of the relay 56 extends from thepositive bus' wire |0| by way of the wire |55 including the controllerswitch 3||yl to a point |51 between the switch 307' and the contact aofothe relay 48, thence by way of a wire |58, a branch wire |59including in series relation therein the contact a of the relay 56 tothe wire |56 and thence through the winding w of relay 56 to thenegative terminal B-` of the source of current.

The contact c of .the cushioning relay 56 is effective in its picked-upor closed position to establish a shunt connection around the resistorcrease of the current in the motoring circuit, and a correspondingincrease in the accelerating torque produced by the motors.

Contact e of relay 56 is effective in its pickedup or closed position toestablish a shunt circuit around contact e of relay 54 for a reasonhereinafter made apparent.

No immediate effect is produced in response to the actuation of thecontacts b and d of the relay 56 to their picked-up or closed positions.

It will thus be seen that the motoring current is successively increasedin two steps by the successive removal of the shunt connection aroundthe field windings of the motors and the shunt connection establishedaround theI resistor 36. This provides a. smooth acceleratingcharacteristic.

When the speed of the motors and consequently the speed of the carincreases in response to the increased torque caused by the increasedmotoring current, the current supplied to the motors automaticallyreduces due to the increasing counter-electromotive force generated inthe motors. When the current supplied to the motors reduces sufficientlythat the voltage-drop across the resistor 52 in the motor circuit isinsufficient to provide adequate current through thel relay 48 tomaintain the relay picked-up, the contacts of the relay 48 are restoredto their dropped-out position.

The restoration of the contact c of the relay 48 to its dropped-out orclosed position does not result in the pick-up of the field shuntingrelay 54 because the self-holding contact a of the relay 54 is in itsopen position. y

The restoration of the contact a of the relay 48 to its dropped-out oropen position is ineffective to cause drop-out of the relay 56 becauseof the self-holding circuit established by the contact a of the relay 56in the manner previously described.

The restoration of the contact b of the relay 48 to its dropped-out orclosed position establishes a circuit for energizing the magnet winding8|a of the stepping relay 42 operating the rheostat 39. This circuitextends from the positive bus wire |0| by way of a branch wire |6I, backcontact e of the field shunting relay 54 in its dropped-out or closedposition, a wire |62, a, wire |63, controller switch g, a wire |64Ifront contact d of the cushioning relay 56 now in its picked-up orclosed position, a wire |65, back contact b of the relay 48, a wire |66,back contact e of the relay 46, a wire |61, back contact e of the relay41, a wire |68, a wire |69, series-connected switch a and Winding 8|a ofthe stepping relay 42, and thence by a wire |18 including limit switch45a to the negative terminal B of the source of current.

The stepping relay 42,/is thus operated in characteristic manner tocause rotation of the ratchet wheel 11, shaft 15 and the brush 92 in thedirection indicated by the double-headed arrow in Fig.

1B ,thus progressively reducing the amount of the resistor 4| of therheostat 39 in the motoring circuit.

If the current supplied to the motors due to the progressive cutting outof the resistor 4| increases above a value suiiicient to cause pick-upof the current limit relay 48, the contacts of the relay 48 are againpicked-up. The consequent actuation of the contact b of the relay 48 toits 36 in the motoring circuit. This causes an in- 75 picked-up or openposition interrupts the eneri gizing circuit, just previously traced,for the magnet winding 8|a of the stepping relay 42 and fur` therrotation of the operating shaft 15 of the stepping relay and of thebrush 92 is thus promptly stopped.

When the speed of the motors increases sumciently following the pick-upof the relay 48 as to cause a sufilcient reduction in the motoringcurrent, due to the increase in the counter-electromotive forcegenerated in the armature windings of the motors, the current limitrelay 48 will again be restored to its dropped-out position. In suchcase, the circuit for energizing the magnet winding 8Ia of the steppingrelay 42 will again be established and rotation of the shaft 15 andbrush l2 continued to effect the further progressive cutout of resistor4|.

It will thus be seen that, during the acceleration period, the steppingrelay 42 is not continuously operated but is operated and stopped inrapid succession until the brush 92 attains the extremity of movement inthe direction indicated by the double-headed arrow in which all ofresistor 4| is cut out of the motor circuit. When this extremity ofrotative movement of the shaft 15 of the stepping relay is attained, thearms 98. It, and |80 cause operation of the limit switches 44, 45, and45A, respectively.

Limit switch 45A is opened and interrupts the circuit for magnet windinglla, thus preventing unnecessary consumption of current by the magnetwinding.

Limit switch 45 is closed but such closing is without effect at thistime.

The engagement of the contact nger b with the contact c of the limitswitch 44 occurring at this time, however, causes energization of thewinding w of the relay 46. 'I'his circuit may be traced from thepositive bus wire ||l| by way of the branch wire |6I, back contact e ofthe field shunting relay 54, wire |62, wire |68, contact fingers b and cof the limit switch 44, wire |15,

. back contact b of the relay 49 in its dropped-out or closed position,a wire |16, winding w of the relay 46, wire |11, front contact b of thecushioning relay 56 to the negative terminal B- of the source ofcurrent.

The contacts of relay 46 are thus actuated to their picked-up positions.

The front contact b of relay 46 is effective in its picked-up or closedPosition to establish a shunt connection around the resistor 81 thuscutting it out of the motor circuit. At the same time, however, thepick-up of the transfer contact l of the relay 46 is effective toreconnect the resistor 4| of the rheostat 89 in the circuit in such -amanner that it may be progressively cut-out of the circuit again uponthe return movement of the brush 92 to its original position, thisreturn movement of the brush 92 being effected in the manner presentlyto be described.

It will be seen that, with the transfer contact f of the relay 46 in itspicked-up position, the circuit for supplying current to the motorsextends from the trolley wire or third rail |4| to the brush 92 of therheostat 38 in the manner previously traced, thence by way of theresistor 4|, a wire |19, transfer contact f of the relay 46 in itspicked-up position, wire |38, transfer contact f of the relay 41 in itsdropped-out position, wire |29, wire |28, including the resistor 38 aswell as contact b of the relay 46 (shunting the resistor 31) andresistor 52, thence by way of the winding wZ of the lock-out relay 59,wire |21, contact b of the brake control relay 51 to th groundconnection at |48.

The resistance of the two resistors 4| and 31 is preferably the same, sothat no change in the resistance of the motor circuit occurs due to thecutting of the resistor 31 out of the circuit and the reinsertion of theresistor 4| in the circuit.

The contacts d and e of the relay 46 are operative in their picked-uppositions to effect a polechanging connection to the windings 8 la and8|b of the stepping relay 42 in such a manner as to render the magnetwinding 8|b operative in response to operation of the current limitrelay 48 instead of the magnet winding 8 la.

Thus. assuming that the current limit relay 48 remains dropped-out atthe time that contact fingers b and c of limit switch 44 are engaged,the circuit for energizing the winding 8|b of the stepping relay 42 isestablished in response to the pick-up of the relay 46. This circuitextends from the positive bus wire IUI by way of the branch wire |5 backcontact e of the eld shunting relay 54, wires |62 and |63, controllerswitch g, wire |64, contact d of the relay 56, wire |65, contact b ofthe current limit relay 48 in its dropped-out or closed position, wire|66, contact d of the relay 46 in its picked-up position, wire |8I,contact d of the relay 41 in its dropped-out position, wire |82, and theseries-connected switch h and magnet winding 8|b of the step ping relay42, to the negative terminal B- of the source of current.

As long as the current limit relay 48 remains dropped-out, therefore,the magnet winding 8Ib is alternately energized and deenergized incharacteristic manner to cause rotation of the ratchet wheel 18 and theshaft 15 in the direction indicated by the single-headed arrow. Themovement of the brush 92 in correspondence with such rotation of theshaft 15 is such as to progressively cut the resistor 4| out of themotoring circuit as it is returned toward its original startingposition.

As the shaft 15 is rotated reversely in the direction of thesingle-headed arrow, the contact arms 98, 89, and |88 arecorrespondingly shifted. Thus the contact finger b of the limit switch44 is restored to its normal position disengaging the contact finger cand engaging the contact finger a, while the contact finger b of thelimit switch 45 is restored to its normal position disengaging thecontact finger a.

Contact finger b of limit switch 45A is restored into engagement withcontact finger a -but such re-closing of this limit switch is withouteffect since the circuit for magnet winding 8|a is not established. Therelays 46 and 41, as previously indicated, are of the slow-acting type.Consequently, the contact finger b of the limit switch 44 reengages thecontact finger a to establish a holding circuit for the relay 46,including the selfholding contact a thereof, thus maintaining the relay46 picked-up thereafter notwithstanding the disengagement of the contactfinger b of the limit switch 44 from the contact finger c.

This holding circuit for the winding of the relay 46 extends from thepositive bus wire I8| by way of the branch wire |6|, contact e of thefield shunting relay 54, lwires |62 and |63, contact fingers b and a ofthe limit switch 44, a wire |85, self-holding contact a of the relay 46,wire |16, winding w of the relay 46, wire |11, and contact b of therelay 56 to the negative terminal B- of the source of current.

The magnet winding 8|b of the stepping relay 42 is alternately energizedand deenergized to continue the retrogressive rotational movement of theshaft 15 and brush 92 under the control of the current limit relay 48 inthe same manner as the magnet winding Bla is controlled by the relay 48.In other words, if the current in the motoring circuit becomessufficient to cause pick-I up of the relay 48, the previously tracedcircuit for energizing the magnet Winding 8| b is interrupted due to theactuation of the contact b of the relay 48 to its picked-up or openposition, thereby causing cessation of `operation of the stepping relay42 andl consequent stopping of rou tation ofthe shaft 15 and brush 92.

1f the acceleration of the motors continues at a sufficient rate, thecurrent limit relay 48 will be restored to its dropped-out position dueto reduction in motoring current caused by increasingcounter-electromotive force generated in the motor armature windings.Thus alternate operation and non-operation of the magnet winding 8|bWill continue until the brush 92 of the rheostat 39 is restored to itsinitial position cutting out all of the resistor 4|. At such time, thecontact arm 98 engages the contact linger b of the limit switch 43 andbends it into engagement with the contact finger c, thereby establishinga circuit for energizing the winding w of the relay 41. This circuitextends from the positive bus wire .by way of the branch wire |6I,contact e of the shunting relay 54, wire |62, contact lingers b and c ofthe limit switch 43, wire |81, back contact c of the current limit relay49 in its dropped-out or closed position, wire |88, front Contact c ofthe relay 46 now in itsy picked-up or closed position, wire |89, windingw of the relay 41, wire |11, and contact b of the relay 56 to thenegative terminal B- of the source of current.

Upon the pick-up of the relay 41, the polechanging contacts d and ethereof are effective to render the magnet winding 8| b of the steppingrelay 42 not operative and the magnet winding 8|a operative. It will beseen that such is the case because tracing the circuit from the positivebus wire IDI to the contact b of the current limit relay 48 in themanner previously described, the circuit continues by Way of the wire|66,

contact d of the relay 46, wire |8|, Contact d of the relay 41, wire|69, switch 85a and magnet winding Bla of stepping relay 42 and thencethrough wire |10 and limit switch 45A to the negative terminal B- of thesource of current.

Contact b of the relay 41 is eiTective in its picked-up position toestablish a short circuit connection around the resistor 38 therebycutting it out of the motoring circuit. At the same time, the transfercontact f of the relay 41 is effective in its picked-up position tochange the i connection -of the resistor 4| in such a manner as torestore it in the motoring circuit. Since resistor 4| has the sameresistance as resistor 38, no change in the resistance of the motorcircuit is produced when resistor 4| is substituted for resistor 38 Thecircuit supplying current to the motors ay now be traced from thetrolley wire `|4| through the motors and the wire |41 to the contact cof the" brake control relay 51, thence by way of the wire |33, brush 92.resistor 4| of the rheostat 39, wire |32, contact f of the relay 41 inits picked-up position, wire |29, Wire |28, contact b of the relay 41, awire ISI, Contact h of the relay 46, a wire |92, wire |28, resistor 52,wir@ |28, winding 102 of the lock-out relay 59, wire |21, and throughthe contact b of the emergency relay 51 to the ground connection at |48.

Assuming that the current limit relay 48 remains in its dropped-outposition, the pick-up of the relay 41 accordingly establishes a circuitfor energizing the magnet winding 9|a. The magnet winding 8|a is thusalternately ener gized and deenergized in its characteristic manner torotate the ratchet Wheel 11, shaft 15, and brush 92 in the directionindicated by the doubleheaded arrow to progressively cutout the resistor4l from the motoring circuit.

When the contact arm 98 leaves the initial position, in which it isshown, in its movement to the opposite extremity of movement thereof,ithe Contact finger b of the limit switch 43 disengages the contactfinger c and engages the contact ringer a thereof. Disengagement of thecontact linger b from the Contact linger c of the limit switch 43interrupts the circuit previously traced for energizing the winding ofthe relay 41, but due to the slow drop-out characteristic of the relay41, a self-holding circuit is established for maintaining the winding ofthe relay 41 ener gized when the contact nger b engages the con tactfinger a of the limit switch 43. This circuit may be traced from thepositive bus wire |01 by way of the branch wire ISI, contact e of thevshunting relay 54, wire |62, contact fingers b and a of the limit switch43, a Wire |93, contact linger a o1' the relay 41 in its picked-up orclosed position, a wire |94, wire |88, contact c of the relay 46 in itspicked-up or closed position, wire |89, winding w of the relay 41, wire|11, and contact b of the relay 56 to the negative terminal B- of thesource of current.

The current limit relay 48 .again functions in its usual manner tocontrol the supply of current to the magnet winding 8|a of the steppingrelay 42 in accordance with the current in the motoring circuit to causethe brush 92 to be progressively shifted in the direction of thedoubleheaded arrow toward the opposite extremity of the resistor 4|whereby to progressively cut the resistor 4| out of the motoringcircuit.

When the brush 92 reaches the extremity of movement thereof in which theentire resistor 4| is cut out of the circuit, the contact arm 99 engagesthe Contact finger b of the limit switch and causes it to engage thecontact ringer a of the limit switch. A circuit is thereby establishedfor energizing the winding of the shunting relay 54 to cause pick-up ofthe contacts thereof and the consequent shunting of the motor eldwindingr |4a, |4b, |4c, and |4d.

The circuit for energizing the winding of the shunting relay 54 justestablished, may be traced from the positive bus Wire |0| bykway of thebranch wire |55 including the controller switch 307', wire |58, Contactc of the relay 41 in its picked-up or closed position, a wire |91,contact lingers a and b of the limit switch 45, wire |38, winding w ofthe relay 54, and thence to the negative terminal BH of the source ofcurrent.

Due to the fact that the closed front contact e of the cushioning relay56 parallels the back contact e of the shunting relay 54, the actuationof the back contact c of the shunting relay 54 to its picked-up or openpositions ineffective to interrupt the holding circuit for the relays 46and 41 previously traced.

With the contact arm |00 of the rheostat 39 engaging the contact nger bof the limit switch 45a and holding it out of engagement with thecontact finger a, the circuit for the magnet winding Bla of the steppingrelay 42 is interrupted independently of the current limit relay 48.Thus, when the car travels at a constant speed corresponding to itsmaximum speed due to the cut out of all of the resistors 36, 31, 38, and4| from ift aecaoce the motoring circuit as is the case at this time,the restoration of the current limit relay 48 to dropped-out position isineffective to cause the continued energization of the magnet windingBia. Unnecessary consumption of current is thus prevented.

(c) Service braking operation Let it now be assumed that the operatordesires to apply the brakes to bring the car to a stop. To do so, theoperator first restores the controller handle 28 to its Coastingposition, holds it there momentarily for reasons hereinafter madeapparent, and then shifts it into the braking zone to a degreecorresponding to the desired degree oi brake application.

When the controller handle 28 is shifted to its casting position fromthe accelerating zone, the corresponding closure of the controllerswitch 30f completes the circuit, previously described, for energizingthe winding of the shunting relay 54 to maintain the shunting relay inits picked-up position. .Lit the same time, the opening of thecontroller switch 307' in the Coasting position of the controller,interrupts the holding circuit for the cushioning relay S, previouslytraced, and this relay is thus restored to its dropped-out po sitlol.

The restoration of the contact c of the relay 5E to its dropped-outposition interrupts the shunt connection around the resistor 35, therebycutting the resistor 35 info the dynamic braking circuit. which isestablished in the manner presently to be described.

The restoration of the contact c of the cushioninoA relay 5B to itsdropped-out or open position errupts the holding circuit for the tworelays and il and these relays are therefore simultaneously restored totheir dropped-out positions.

The dropout of the contact b of each of the relays 25 and 4l' removesthe shunt connection around the resistors 37 and 38. respectively, andthese resistors are therefore cut into the dynamic braking circuitestablished in the manner presently to be described.

The restoration of the contact f of each of the relays 45 and 4i fo thedropped-out position reconnects the resistor 4| of the rheostat 39 inthe circuit with the resistors 31 and 38, the amount oi the resistor 4|included in the circuit dependine upon the position of the brush 92. Ifthe brush 92 is in its extreme right-hand position. the entire resistoris cut-out of the circuit.

The restoration of the controller switch 30h to its dropped-out or openposition in response to the restoration of the controller handle 28 tothe Coasting position thereof interrupts the circuit for energizing thewinding of the brake control :relay and the contacts of this relay arethus restored to their dropped-out positions, thereby establishing thedynamic braking circuit pre viously described. At this time, however,with he field shunting relay 54 picked-up, the i'leld shuntingconnections are established around the 1lnotor field windings bycontacts b and c and coniuently relatively low dynamic braking current sin the circuit. Negligible dynamic bra f eilcct is thus exerted at thistime.

En the Coasting position of the controller handle The sensitivity of therelays 4E and 49 to 'the current fiowing in the dynamic braking circuitis thus increased.

Under the circumstances described, the degree of the current in thedynamic braking circuit is substantially proportional to the speed oftravel of the car. The current limit relays 48 and 49 thus respond tothe current in the dynamic braking circuit as a measture of the speed oftravel of the car.

Ii the degree of resistance in the dynamic braking circuit for theparticular speed of the car is such that insufficient current issupplied to energize the winding of the current limit relay 48 to causepick-up thereof, a circuit for energizing the magnet winding Bla of thestepping relay 42 is established assuming that the brush 92 is not inits extreme right-hand position. This circuit may be traced from thepositive bus wire |0| by way of a branch wire 20| including thecontroller switch 30i, a Wire 20?. to the Wire |65, thence by way oi thecontact b of the current limit relay 48, wire ISE, contact e of therelay 4G in its droppedout position, wire |01, contact e of the relay 41in its dropped-out position, Wires |68 and |69, switch a and magnetwinding Bia of the stepping relay 42., wire |10, and the closed contactsb and o1" the limit switch 45A to the negative terminal B ci the sourceof current.

The brush 92 is accordingly stepped around in the direction indicated bythe double-headed arrow to its extreme right-hand position cutting outall of the resistor 4| of the rheostat 39.

At such time, if deenergization of the magnet winding Bia is noteffected in response to the pick-up of the current limit relay 48, suchdeenergization is effected in response to the separation of the contactfingers b and a of the limit switch 45A.

On the other hand, if the current in the dynamic braking circuit for aparticular speed oi the car is suiiicient to cause pick-up not only ofthe contacts oi the current limit relay 48 but also the contacts of thecurrent limit relay 49, a circuit is established for energizing themagnet winding 8| b of the stepping relay 42 to cause the brush 92 to beshifted in the left-hand direction indi` cated by the single-headedarrow to out an additional portion of resistor 4| into the circuit.

The circuit for energizing the magnet winding 8|b extends from thepositive bus Wire |0| by way of the branch wire 20| including thecontroller switch 302', wire 202, wire |65, a branch wire 203 includingthe front contact a of the current limit relay 49, contact d of therelay 46 in its dropped-out position, wire |8I, contact d of the relay4l in its dropped-out position, wire |82, and switch 85h and the magnetwinding 8|b of the stepping relay 42 to negative terminal B- of thesource of Current.

This operation of the rheostat 39 in the Coasting position of thecontroller handle 28 is termed the spotting operation and is for thepurpose of adjusting the resistance in the dynamic braking circuit morenearly in accordance with the actual speed of the car so as to minimizethe time required to adjust the resistance in the dynamic brakingcircuit to the degree corresponding to the degree oi braking called forwhen the controller is subsequently shifted into the braking zone.

Now let it be assumed that the operator shifts the controller handle 28into the braking zone, for example, to braking position 3.

cwitch 39e is operated to open position in the current limit relays 48and 49.

braking position I and remains open thereafter for all braking positionsof the controller handle 28. Consequently when controller handle 28 isshifted to braking position 3, as assumed, the circuit for energizingthe winding wl of the lockout relay 59 is interrupted. The lock-outrelay S59, however, has the winding w2 thereof energized by the currentin the dynamic braking circuit and accordingly is maintained inpicked-up position. The lock-out relay 59 has a slowactingcharacteristic in order to provide a short interval of time in which topermit the build-up of dynamic braking current sufficient to energizethe winding w2 to a degree necessary to maintain the lock-out relaypicked-up.

In the braking position t, controller switch 30f is restored to openposition thereby interrupting the circuit established thereby forenergizing the winding of the eldshunting relay 54. At the same time,the holding circuit for the winding of the relay 54 is interrupted dueto the ope-ning of the controller switch 30k in the braking position Iand subsequent braking positions. Thus, regardless of whether thecurrent limit 48 is picked--up or dropped-out when the controller handlereaches braking position I, the field shunting relay 54 is instantlyrestored to its droppedout position.

The drop-out of the eld shunting relay 54 is accordingly effective toopen the shunt connec tions around the motor eld windings duc to thedrop-out or opening of the contacts b and c thereof. The fullenergization of the eld winding of the motors is accordingly effectedand a substantial increase in the degree of dynamic braking current andconsequently in the degree of dynamic braking effect is produced.

When the controller handle 28 leaves the Coasting position, thecontroller switch 30e is again restored to open position, therebycutting the resistor into the circuit of the windings of the At the sametime, the brush or contact arm 33 of the rheostat 32 associated with thecontroller 2'I is shifted to insert a portion of the resistor 32athereof into circuit relation with the windings of the current limitrelays 48 and 49 to render them operatively sensitive in accordance withthe degree of displacement of the controller handle out of its Coastingposition in exactly the same manner as for acceleration. In other words,as the degree of displacement of the controller handle 28 out of itsCoasting position increases, resistance is progressively inserted oradded in the circuit of the windings of the current limit relays 48 and49, thereby requiring a higher current in the dynamic braking circuitproportional to the degree of displacement of the controller handle outof Coasting position to cause pick-up of the current limit relays 48 and49.

The restoration of the contact d of the field shunting relay 54 to itsdropped-out or closed position is ineffective at this time to causeenergizaticn of the winding of the cushioning relay 56 for the reasonthat the controller switch 301' is in open position. It will thus beseen that the cushioning relay 56 remains dropped-out during f thebraking operation as does the field shunting relay 54,

Assuming that the brush 92 is in its left-hand position in which theresistor 4I of the rheostat 39 is fully cut into the dynamic brakingcircuit, and that the dynamic braking current initially established uponthe drop-out of the eld shuntcurrent limit relay 48.

ing relay 54 is in excess of that required to prow duce the degree ofdynamic braking called :for by the controller 21, both the current limitrelays 48 and 49 will be picked-up. A circuit will thus be establishedfor energizing the magnet winding 8Ib of the stepping relay 42 but dueto the fact that the brush arm 92 is already in a position cutting inall of the resistance 4I, the energizan tion of the magnet Winding SIbis without effect. The circuitthus established for energizing the magnetwinding 8Ib extends from the positive bus wire IUI by way of the branchwire ISE, back Contact e of the field shunting relay 54 in itsdropped-out or closed position, wires I 52 and 63. controller switch 30hnow in its closed position, wire 202, wire i65, front contact o: of thecurrent limit relay 45 now in its picked-up or closed posi-n tion, wire203, contact d of the relay 46 in its dropped-out position, wire IBI,contact ci of the relay 41 in its dropped-out or closed position, wire|82, and switch h and the magnet winding 8Ib of the stepping relay 42 tothe negative terminal B- of the source of current. y

If, at the time the shunting relay 54 drops out, the dynamic brakingcurrent is sufficient to cause pick-up of only the current limit relay48 and not of the current limit relay 49, a circuit is correspondinglyestablished for energizing the magnet winding Sla of the stepping relay42. This circuit extends from the positive bus Wire IUI to thecontroller switch 30h as previously traced, thence by way of the Wires202 and I65, back contact b of the current limit relay 48, wire iSd,Contact e of the relay 46, Wire itil', contact e ci the relay 41, Wires|68 and ISS, switch 85a and the magnet winding Bla of stepping relay42,k

wire |10, and the contact nngers a and b of the limit switch 45A to thenegative terminal B- of the source of current. The stepping relay 42 isaccordingly operated to shift the brush 92 in the right-hand directionindicated by the double-headed arrow to progressively cut out resistor4I from the dynamic braking circuit in accordance with the controlexercised by the That is, if the dynamic braking current produced inresponse to the cutting out of the resistor 4I is suicient to pick-upthe contacts of the current limit relay 48, the circuit for the magnetwinding 8Ia will be interrupted at contact b of the current limit relay48 and further movement of the brush 92 Will be stopped until such timeas the dynamic braking current again reduces suciently to permit dropoutof the contacts of the current limit relay 48. The stepping relay 42will thus be opera-ted to shift the brush 92 in steps until it reachesthe extreme right-hand position thereof in which the entire resistor 4Iis cut out of the dynamic brak ing circuit.

If the brush arm 92 had been in its extreme right-hand position cuttingout all of the re sistor 4I at the time the field shunting relay 54 isdropped-out, the operation now about to be described would beimmediately effected in response to the drop-out of the relay 54.

Due to the fact that the contact linger b is caused to engage thecontact nger c of the limit switch 44 by engagement of the contact arm98 with the Contact finger b, a circuit is established for energizingthe Winding w of the relay 46. This circuit extends from the positivebus wire IUI, by way of the branch wire ISI, contact e of the eldshunting relay 54, wires i62 and |53, contact fingers b and c of thelimit switch 44, Wire I 15, back contact b of the current limit relay49, wire |16 winding w of the relay 46, wire |11, and a branch wire 205including the controller switch 30d which is closed in the coastingposition and all braking positions of the controller 21, to the negativeterminal B- of the source of current.

The contacts of the relay 46 are accordingly actuated to their picked-uppositions. The contact b of the relay 46 is effective in its picked-upor closed position, as during acceleration, to shunt the resistor 31 andthereby cut it out of the dynamic braking circuit. t the same time, thecontact f of the relay 46 is effective in its pickedup position toreconnect the resistor 4| in the dynamic braking circuit in the samemanner as described during the accelerating operation.

If the dynamic braking current at this time is still insunicient tocause pick-up of the contacts of the current limit relay 48, a circuitis accordingly established for energizing the magnet winding 8|b of thestepping relay 42. This circuit extends from the positive bus wire I| byway of the branch wire |6I, contact e of the shunting relay 54, wires|62 and |63, controller switch 30h, wires 202 and |65, back contact b ofthe current limit relay 48, wire |66, Contact d of the relay 46 in itspicked-up position, wire |8|, contact d of the relay 41 in itsdropped-out position, wire |82, and switch 85h and magnet winding 8|b ofthe stepping relay 42 to the negative terminal B- of the source ofcurrent.

The stepping relay 42 is accordingly operated to shift the brush 92 inthe left-hand direction indicated by the single-headed arrow toprogressively cut resistor 4| out of the dynamic braking circuit untilsuch time as the dynamic braking current produced is sufficient to causepick-up of the contacts of the relay 48. At such time, pickup of thecontact b of the relay 48 interrupts the circuit for the magnet winding8| b and further movement of the brush 92 is stopped until the dynamicbraking current again reduces sufciently to permit the drop-out of thecontact b of the relay 48.

Movement of the brush arm 92 in the left-hand direction continues untilthe contact arm 98 causes the contact finger b of the limit switch 43 toengage the contact finger c and thereby establish a circuit forenergizing the winding w of the relay 41.

This circuit extends from the positive bus wire |0| by way of the branchwire |6I, contact e of the shunting relay 54, wire |62, contact fingersb and c of the limit switch 43, wire |81, back contact c of the currentlimit relay 49 in its dropped-out position, wire |88, contact c of therelay 46 in its picked-up position, wire |89, winding w of the relay 41,wire |11, and wire 205 including the switch 30d to the negative terminalB- of the source of current.

Contact b of relay 41 is effective in its pickedup or closed position toestablish a shunt connection around the resistor 38, thereby cutting itout of the dynamic braking circuit. At the same time, contact f' of therelay 41 is effective in its picked-up position to reconnect theresistor 4| in the dynamic braking circuit.

If the dynamic braking current at this time is insufficient to causepick-up of the contacts of the current limit relay 48, a circuit isestablished in response to the pick-up of the relay 41 to causeenergization of the magnet winding 2id of the stepping relay. Thiscircuit extends from the positive bus wire 0| by way of the branch wirecontact e of the field shunting relay 54, wires |62 and |63, controllerswitch 30h, wire 202, wire |65, back contact b of the current limitrelay 48, wire |66, contact d of the relay 46 in its picked-up position,wire |8|, contact d of the relay 41 in its picked-up position, wire |69,switch a and the magnet winding 8|a of the stepping relay 42, wire |10,and the closed limit switch 45A to the negative terminal B- of thesource of current.

The stepping relay 42 is accordingly operated to shift the brush 92 inthe right-hand direction, indicated by the double-headed arrow toprogressively cut resistor 4| out of the dynamic braking circuit. As inprevious instances, if the dynamic braking current increasessufficiently in response to movement of the brush 92 to cause pick-up ofthe current limit relay 48, contact b of the relay 48 is correspondinglypicked-up to interrupt the energizing circuit for magnet Winding 8|a ofthe stepping relay 42 and further movement of the brush 92 is stopped.

The current limit relay 48 is accordingly effective to regulate thedegree of dynamic braking current in accordance with the setting of thecontroller handle 28 to effect a corresponding degree of dynamic brakingeffect until such time as the brush 92 of the rheostat 39 reaches therighthand extremity of movement at which time the entire resistor 4| isagain cut out of the circuit. Thereafter, no further resistance remainsto be cut out of the dynamic braking circuit and the degree of dynamicbraking effect is determined solely in accordance with the speed of thecar. The dynamic braking effect in characteristic manner thereforereduces with reducing speed of the car.

When the dynamic braking current reduces to a sufficiently low degree asthe car approaches a stop, the current energizing the winding w2 of thelock-out relay 59 is insufficient to maintain the contact of the relayin its picked-up position and the contact is accordingly restored to itsdroppedout position.

The restoration of the contact of the lock-out relay 59 to itsdropped-out or open position interrupts the circuit, previously traced,for maintaining the winding wl of each of the relays 66 and theassociated auxiliary solenoids 2lb of the spring-applied brake devicesenergized.

Upon deenergization of the solenoids 2| b, the spring-applied brakes areapplied on the brake drums of the corresponding motor shafts. Thereduction in the degree of dynamic braking effect, as the car approachesa stop, is thus counteracted to some extent by the braking effectexerted by the spring-applied brakes. The spring-applied brakes remaineffective thereafter and while the car is stopped, as a parking brake.

Now let it be supposed that initially or at some time during the brakeapplication the operator shifts the controller handle 28 to brakingposition 4. In such case, the dynamic braking operation is effected aspreviously described. In this connection, the resistor of the rheostat32 associated with the controller 21 is so arranged that no additionalresistance is cut into the circuit of the windings of the current limitrelays 48 and 4,9 in braking position 4 and 5 of the controller.Consequently, the current limit relays 48 and 49 function to regulatethe degree of the dynamic braking effect to the same degree as inbraking position 3.

With the controller handle 28 in braking position 4, the switch 3071 isclosed, thereby energizing the winding of the relay 62 and establishingin the circuit of the magnetic track brake windings a. The magnetictrack brake devices 25 are accordingly operated into frictionalengagement with the track rails and exert a braking veffect on the caradditional to that provided by the dynamic brake.

If the operator shifts the controller handle 28 to braking position 5,controller switch 30m is also closed and thereby establishes the circuitfor energizing the relay 63. Relay 63 is thus actuated to shunt theresistor 65 to cut it out of the circuit of the magnetic track brakewindings 25a. The current energizing the magnetic track brake windings25a is thus increased correspondingly to increase the degree of brakingeffect produced by the magnetic track brake devices.

If the operator further shifts the controller handle 28 to the brakingposition 6, no further increase in the degree of energization of themagnetic track brake windings takes place. A higher degree ofapplication of the magnetic track brakes may, however, be effected inthe Emergency position of the controller handle, as explainedhereinafter.

It will be noted that as the controller handle 28 is shifted to brakingposition 6 the amount of the resistor 32a of the rheostat 32 included inseries circuit with the windings of the current limit relays 48 and 49is correspondingly increased so that the current limit relays arecorrespondingly conditioned to regulate the dynamic braking current andthus the dynamic braking effect to a correspondingly higher degree.

It will accordingly be seen that the degree of dynamic braking eilectproduced during service braking applications is in accordance with thedegree of displacement of'the controller handle 28 from the Coastingposition and that the magnetic track brakes are not applied until aftera predetermined degree of displacement of the controller handle hastaken place, after which 'the degree of magnetic track brake effect isprogressively increased in steps. In all cases, the springapplied brakesare automatically applied only as the car approaches a stop in responseto the dropout of the lock-out relay 59, controlled by the degree ofdynamic braking current.

(d) Emergency braking operation Emergency application of the brakes maybe effected by the operator shifting the controller handle 28 to itsEmergency position wherein controller switch 30a is opened, or by theoperator intentionally or accidentally releasing the dowm ward pressureon the controller handle 28 to open the deadman switch 29, or byoperation of the conductors switch 1| to its open position. Any of theabove operations interrupts the emergency wire circuit, previouslytraced, and causes deenergization of the emergency relay -58 and aconsequent drop-out of the contacts thereof.

The drop-out of the emergency relay 58 interrupts the circuit for thebrake control relay 51 if this circuit has not previously beeninterrupted at controller switch 30h, as might be the case when thecontroller handle 28 is in an accelerating position and the operatorrelieves the pressure on the controller handle to cause opening of thedeadman switch 29 or opening of the conductors switch 1l occurs.

If the brake control relay 51 has already been restored to itsdropped-out position in response to the opening of the controller switch30h then the drop-out of the emergency relay 58 is without effect as torelay 51.

The restoration of the contact b of the emergency relay 58 to itsdropped-outglgpen position interrupts the circuit for energizing thewinding wl of the lock-out relay 59 to cause dropout of the relay in theevent that the controller handle is in an accelerating position and hasnot been shifted to a braking position to open controlled switch 30e.

The restoration of the back contact c of the emergency relay 58 to itsdropped-out or'closed position establishes a shunt connection around theresistors 31, 38 and 4|, thereby promptly cutting substantially all ofthe resistance out of the dynamic braking circuit.

In the case of an emergency application of the brakes initiated byoperation of the deadman switch 29 or by the conductors switch 1I, withthe controller handle 28 in an accelerating position, the holdingcircuit for the cushioning relay 56 remains established and the relaythus remains picked-up. Consequently the resistor 36 in the dynamicbraking circuit remains shunted, that is, cut out of the circuit. Thisprovides a slightly higher dynamic braking current than in the case ofan emergency application of the brakes initiated by operation of thecontroller handle 28 to Emergency position. It will be seen that this isso because when the controller handle 28 is operated to Emergencyposition, the pick-up and holding circuits for the cushioning relay 56are both interrupted due to the open position of the controller switch30j. Thus with relay 56 dropped-out, resistor 36 is cutinto the dynamicbraking circuit,

In the case of an emergency application of the brakes, initiated byoperation of the controller handle 28 to its Emergency position, fieldshunting relay 54 is deenergized because of the interruption of theholding circuit therefor in response to the opening of the controllerswitch 30k. In the case of an emergency application of the brakesinitiated by operation of the deadman switch 29 or the conductors switch1l, with the controller handle 28 in an accelerating position and thecontroller switch 30k correspondingly in closed position, deenergizationof the winding of the shunting relay 54 is effected in response to thepick-up of the current limit relay 48 resulting from the high initialdegree of dynamic braking current, the contact c of the relay 48 beingthus correspondingly actuated to its picked-up or open position.

In either case, therefore, the field shunting relay 54 is restored toits dropped-out position.

during the emergency application of the brakes and consequently theshunt connection around the field windings of the motors is removed.

It will thus be seen that the maximum degree of dynamic braking currentis produced in an emergency application of the brakes and a consequentlymaximum degree of dynamic braking eiect is produced.

Variations of the dynamic braking current produced in response tovariations in the speed of the car may cause a response of the currentlimit relays 48 or 49, which will operate in the usual manner to controlthe magnet windings 8| a and Bib of the stepping relay 42 and operationof the relays 46 and 41. However, with all of the resistors 31, 38, and4|v shunted by contact c of the emergency relay, such operation iswithout effect except to vary such resistance more or less in accordancewith the speed of the car.

The contact d of the emergency relay 58 is effective when restored toits dropped-out or closed position to establish a circuit jointly withcontroller switch 3D1 for energizing the winding of the relay 63. At thesame time contact e of emergency relay 58 is effective in its droppedoutor open position to open the circuit of the winding of relay 62, thusinsuring drop-out of relay E2 if it is not already dropped-out. Thepick-up of the relay 63 is thus effective to establish the circuit forenergizing the magnet windings 25a of the magnetic track brake devicesto a maximum degree.

Due to the slow-acting characteristic of the lock-out relay 59, thedynamic braking current builds-up sufficiently to cause winding w2 tomaintain the relay picked-up until the car reduces to a low speed inapproaching a stop. At such time, the contact of the lock-out relay 59is restored to its dropped-out position, thereby opening the circuit ofthe winding w2 of the relays 66 and of the auxiliary solenoids 2lb ofthe spring-applied brake devices. The springapplied brake devices arethus applied in the same way as in a service application of the brakes,that is, only when the car approaches a stop and remain applied untilsuch time as the car is again started.

If the operator desires to remove the controller handle 28, he mustfirst shift it to the Non-operative position before the removal may beeffected, as previously stated. In the Non-operative position of thecontroller handle, the various controller switches are all operated toopen position, thereby deenergizing all of the relays or windings notpreviously deenergized and preventing the discharge of current from thesource. Thus, in the Non-operative position of the controller handle,the controller switch 301 opens the circuit for the winding of the relayB3, thereby deenergizing the magnetic windings 25a of the magnetic trackbrake devices automatically notwithstanding the fact that the emergencyreiay 5B is in its dropped-out position. Of course, the spring-appliedbrakes remain applied while the controller handle is removed because thesolenoids 2id and 2lb are both deenergized.

Whenever the operator desires to start the car, following an emergencyapplication of the brakes initiated by the operation of the deadmanswitch or conductor switch, these switches must first be closed beforethe car can be started in order to cause the emergency relay 58 to againbe re stored to its normal picked-up position.

When the operator desires to start the car after having removed thecontroller handle, he merely restores the controller handle to theoperating shaft of the controller 21 and shifts it from theNon-operative position to the Coasting position. The apparatus isaccordingly conditioned in the manner previously described andacceleration or braking may be effected as previously described. It willbe understood, of course, that ii the controller handle 28 is shiftedfrom the Coasting position to a braking position while the car is at astandstill, there can of course be no application of the dynamic brakes.Thus the lock-out relay 59 will be instantly restored to its dropped-outposition and the spring-applied brake will be instantly applied, andremain applied in all braking positions of the troller handle. Themagnetic track brake devic will of course be applied in varying degreeas the controller handle is progressively shifted into service brakingpositions l, 5, and 6 and Emergency position.

SUMMARY summarizing, it will be seen that I have disclosed a propulsionand braking control system for a vehicle, such as a railway car, havingpropulsion motors and wherein a plurality of electrical braking devicesare employed including the propulsion motors of the car acting asdynamic brakes, electromagnetic track brakes, and electricallycontrolled spring-applied parking brakes of the friction type.

A combination propulsion and braking controller is provided having asingle controller handle shiftable in one direction from a. Coastingposition into the accelerating zone thereof and in the oppositedirection from the Coasting position into the braking zone thereof. Thedegree of displacement of the controller handle out of Coasting positioninto the accelerating zone determines the rate of acceleration of thecar. Similarly, the degree of displacement of the controller handle outof Coasting position into the braking zone determines the degree ofbraking effect produced and consequently the rate of deceleration orretardation of the car.

The propulsion motor control includes mechanism automatically controlledaccording to the current supplied to the propulsion motors or accordingto the dynamic braking current to progressively cut-out resistance orprogressively insert resistance to control the rate of acceleration orthe degree of dynamic braking effect in accordance with the position ofthe controller handle. The automatic mechanism for controlling theresistance in the motor circuit, both during accelerating and brakingoperations, includes a rheostat which is operated in one or the otherdirection to cut-oui; or insert resistance in the motor circuit by meansof a stepping relay. The arrangement is such that when the rheostat isoperated to cut-out all of the resistance thereof from the motorcircuit, a change of connections is effected to reinsert the resistanceof the rheostat in the circuit while cutting-out an equivalentresistance from the motor circuit. Thus a. major variation in the amountof resistance in the motor circuit may be produced progressively byprogressively varying the resistance of a rheostat having a fraction ofthe total resistance in Athe motor circuit repeatedly. This generalprinciple of operation is broadly not my invention, because it isdisclosed in the above mentioned Tritle Patent 2,120,956. The specificmechanism which I provide, including particularly the rheostat operatedby a stepping relay whereby the operation is effected, is howeverbelieved to be novel.

The system further includes an apparatus whereby magnetic track brakedevices are applied upon a predetermined displacement of the brakecontroller out of Coasting position and whereby the degree ofapplication of the magnetic track brakes is progressively increased asthe displacement of the controller handle out of Coasting positionthereafter increases.

A lock-out relay is provided whereby to maintain spring-appliedsolenoid-released brakes in release position in response to the dynamicbraking current until such time as the dynamic braking current reducesto a low degree at the time the speed of the car is reduced to a lowdegree as it approaches a stop. At such time, application of thespring-applied brakes is automatically effected. The spring-appliedbrakes thus serve as a parking brake and'also to supplement orcompensate for the diminution in the degree of dynamic braking effect atlow speed.

Emergency applications of the brakes may be produced either by operationof the combination propulsion and brake controller, or by a deadmandevice, or by a conductorls switch. In an emergency application of thebrakes, maximum dynamic braking and maximum magnetic track braking isautomatically produced substantially instantaneously. As in serviceapplications ci the brakes, the spring-applied solenoid-released brakesare suppressed for the major portion of the braking cycle and appliedonly when the car reduces to low speed.

Having now described my invention, what I claim as new and desire tosecure by Lettere Patent, is:

1. In a motor control system, the combination of means for establishinga motor circuit, a-plurality of motor controlling resistors in the motorcircuit, a reversible stepping relay operative in cpposite directionsbetween two extreme positions thereof to progressively vary the amountof one of said resistors included in the motor circuit, means controlledaccording to the current in the motor circuit for controlling theoperation of said stepping relay, means eiective in response to thecomplete exclusion of said resistor from the motor circuit followingoperation oi said stepping relay in one direction to one extremeposition for causing another of said resistors to be cut out of themotor circuit and for causing said one re sistor to be reconnected intothe motor circuit in a manner to be progressively excluded from thecircuit in response to operation of the stepping relay in the oppositedirection, said last means being eiective to control the stepping relayin a manner to reverse the direction of operation of said stepping relaywhenever it reaches an extreme position thereof.

2. In a motor control system, the combination of means for establishinga motor circuit, a plurality of motor controlling resistors in the motorcircuit, a stepping relay operative reversibly between two extremepositions for progressively varying the amount of one of said resistorsin cluded in the motor circuit, means controlled acmeans effective whenthe stepping relay reaches said other extreme position in which the saidone resistor is again completely excluded from the motor circuit forcutting another of said resistors out of the motor circuit, forreversing said stepping relay, and for reconnecting the said oneresistor in the circuit in a manner such that movement of the steppingrelay toward the said one extreme position is again eiective toprogressively exclude said resistor from the motor circuit.

3. In a motor control system, the combination of means for establishinga motor circuit, a resistor in the motor circuit, a reversible steppingCTI relay operative in one direction to progressively exclude saidresistor from the motor circuit and operative in the opposite directionto progressively include said resistor in the motor circuit, and a pairof current-responsive devices one of which is operatively responsive toa certain current in the motor circuit and the other of which isoperatively responsive to a certain higher current in the motor circuit,said current-responsive devices cooperating to control said steppingrelay in such a manner that so long as both of said currentresponsivedevices are not operated operation of the stepping relay to causeprogressive exclusion of said resistor from the motor circuit iseffected, that when said one current-responsive device only is operatedoperation of the stepping relay is stopped, and that when both of saidcurrentresponsive devices are operated operation of said stepping relayto cause progressive inclusion of said resistor in the motor circuit iseffected.

4, In a motor control system, the combination of means for establishinga motor`circuit, a resistor in the motor circuit, a reversible steppingrelay operative in one direction to progressively exclude said resistorfrom the motor circuit and operative in the opposite direction toprogressively include said resistor in the motor circuit, a pair ofcurrent-responsive devices one of which is operatively responsive to acertain current in the motor circuit and the other of which is opera.-tively responsive to a certain higher current in the motor circuit, saidcurrent-responsive devices cooperating to control said stepping relay insuch a manner that so long as both of said currentresponsive devices arenot operated operation of the stepping relay to cause progressiveexclusion of said resistor from the motor circuit is elTected,

that when said one current-responsive device only is operated operationof the stepping relay is stopped, and that when both of saidcurrentresponsive devices are operated op/eration of said stepping relayto cause progressive inclusion of said resistor in the motor circuit iseffected, and means for varying the degree of current in the motorcircuit to which said current-responsive devices are respectivelyoperatively responsive.

5. In a motor control system, the combination of a controller shiftabledifferent degrees out of a certain position and eiective thereby toestablish a motor circuit, a resistor in the motor circuit, a.reversible stepping relay operative in o e direction to progressivelyexclude said resistor from the motor circuit and operative in theopposite direction to progressively include said resistor in the motorcircuit, a pair of current-responsive devices one of which isoperatively responsive to a certain current in the motor circuit and theother of which is operatively responsive to a certain higher current inthe motor circuit, said current-responsive devices cooperating tocontrol said stepping relay in such a manner that so long as both ofsaid current-responsive devices are not operated operation of thestepping relay to cause progressive exclusion of said resistor from themotor circuit is effected, that when said one curwhich the currentresponsive devices are respectively operatively responsive.

6. In a motor control system, the combination of means providing a motorcircuit, a motor controlling resistor in the motor circuit, a steppingrelay having a rotary armature and two windings one of which iseil'ective upon repeated alternate energization and deenergization tocausestep-bystep rotation of the armature of the relay in one directionand the other winding of which is eiIective upon repeated alternateenergization and deenergization to cause step-by-step rotation of thearmature in the opposite direction, means operated by the armature ofthe stepping relay for progressively increasing or decreasing the amountof said resistor in the motor circuit depending upon the direction ofrotation of the armature, and means controlled according to the currentin the motor circuit for selectively rendering one or the other of saidwindings operative.

7. In a motor control system, the combination of means providing a motorcircuit, a motor controlling resistor in the motor circuit, a steppingrelay having a rotary armature and two windings one of which iseffective upon repeated alternate energization and deenergization tocause step-bystep rotation oi the armature of the relay in one directionand the other winding of which is eiective upon repeated alternateenergization and deenergization to cause step-by-step rotation of thearmature in the opposite direction, means operated by the armature ofthe stepping relay for progressively increasing or decreasing the amountof said resistor in the motor circuit depending upon the direction ofrotation of the armature, and means for causing selective operation ofsaid windings in a manner such that the current in the motor circuit isregulated to a substantially constant value.

8. In a motor control system, the combination of means providing a motorcircuit, a motor controlling resistor in the motor circuit, a steppingrelay having a rotary armature and two windings one of which is eiectiveupon repeated alternate energization and deenergization to causestep-bystep rotation of the armature of the relay in one direction andthe other winding of which is effective upon repeated alternateenergization and deenergization to cause step-by-step rotation of thearmature in the opposite direction, means operated by the. armature ofthe stepping relay for progressively increasing or decreasing the amountof said resistor in the motor circuit depending upon the direction ofrotation of the armature, means for causing selective operation of saidwindings in a manner such that the current in the motor circuit isregulated to a substantially constant value, and means controlling thelast said means in a manner to render said last means eiectve to causeregulation of the current in the motor circuit to any one of a pluralityof selected substantially constant values.

9. In a mot-or control system, the combination of means providing amotor circuit, a motor controlling resistor in the motor circuit, astepping relay including a rotary armature and two windings, one of saidwindings being effective upon repeated alternate energization anddeenergization to progressively rotate the armature in one direction andthe other of said windings being effective upon repeated alternateenergization and deenergization to progressively rotate the armature inthe opposite direction, means movable according to the rotary movementof the armature of said stepping relay ior progressively decreasing orprogressively increasing the amount of said resistor in the motorcircuit depending upon the direction of movement thereof, twocurrent-responsive devices, and means associating saidcurrent-responsive devices with the motor circuit in such a manner thatone of said current-responsive devices is operatively responsive only toa current in the motor circuit exceeding a. certain value and the otheroi' said current-responsive devices is operatively responsive only to acurrent in the motor circuit exceeding a certain higher value, said twocurrent-responsive devices cooperating in such a manner that when bothof said current-responsive devices, are not operated one o! the windingsof said stepping relay is alternately energized and deenergized so as tocause operation of the armature in one direction to cause a progressivedecrease of the amount of the resistor in the motor circuit, so thatwhen only said one of the current-responsive devices is operated both ofthe windings oi said stepping relay are deenergized and operation o1'the stepping relay thereby stops, and so that when both o! saidcurrent-responsive devices are operated the other .L of the windings ofsaid stepping relay is alternately energized and deenergized to causeoperation of the amature of the stepping relay in a direction to cause aprogressive increase in the amountof said resistor in the motor circuit.

10. In a motor control system, the combination of means for establishinga motor circuit, a motor controlling resistor in the motor circuit, astepping relay including a rotary armature and two windings, one of saidwindings being eilective upon repeated alternate energization anddeenergization to progressively rotate the amature in one direction andthe other of said windings being effective upon repeated alternateenergization and deenergization toprogressively rotate the armature inthe opposite direction, means movable in accordance with the movement ofthe armature of said stepping relay in one direction to progressivelydecrease the amount o! the resistor in the motor circuit and inaccordance with the movement of the armature of the stepping relay inthe opposite direction to progressively increase the amount of theresistor in the motor circuit, and means responsive to the current inthe motor circuit for controlling the windings o1' said stepping relayin such a manner that when the current in the motor circuit is less thana certain value one of said windings is alternately energized anddeenergized repeatedly, when the current in the motor circuit exceedssaid certain value but is less than a certain higher value both of saidwindings are deenergized, and when the current in the motor circuitexceeds said certain higher value the other of said windings isalternately energized and deenergized repeatedly.

ll. In a motor control system, the combination of a controller operativedifferent degrees out of a certain position to establish a motorcircuit, a motor controlling resistor in the motor circuit, a, steppingrelay including a rotary armature and two windings, one of said windingsbeing eiective upon repeated alternate energization and deenergizationto progressively rotate the armature in one direction and the other ofsaid windings being effective upon repeated alternate energization anddeenergization to progressively rotate the armature in the oppositedirection, means movablein accordance with the movement oi' the armatureoi said stepping relay in one direction to progressively decrease theamount oi the resistor inthe motor circuit and in accordance with themovement of the armature of the stepping relay in the opposite directionto progressively increase the amount of the resistor in the motorcircuit, means responsive to the current in the motor circuit forcontrolling the windings of said stepping relay in such a manner thatwhen the current in the motor circuit is less than a certain value oneof said windings is alternately energized and deenergized repeatedly,when the current in the motor circuit exceeds said certain value but isless than a certain higher value both of said windings are deenergized,and when the current in the motor circuit exceeds said certain highervalue the other of said windings is alternate-1y energized anddeenergized repeatedly, and means effective in accordance with thedegree of displacement of the controller out of its certain position forprogressively increasing the said certain value of current and the saidycertain higher value of current in the motor circuit to which the lastsaid means is responsive.

12. In a control system for a motor having a field winding, thecombination of a controller operative out of a certain position toestablish a motor circuit, a shunting relay effective when picked-up toshunt the eld winding of the motor and when dropped-out to remove theshunt connection from the eld Winding, means effective in the saidcertain position of the controller for causing pick-up of said relay,means for establishing a holding circuit for maintaining said shuntingrelay picked-up when said controller is initially moved out of its saidcertain position, current-responsive means responsive to the-current inthe motor circuit and effective to interrupt said holding circuit tocause drop-out of said shunting relay when the current in the motorcircuit exceeds a certain value, a motor controlling resistor in themotor circuit, operating means for progressively excluding said resistorfrom the motor circuit, and means effective in response to the drop-outof the shunting relay for rendering said current-responsive meanseffective to control the said operating means in a manner to cause it toprogressively exclude said resistor from the motor circuiti 13. In acontrol system for a motor having a field Winding, the combination of acontroller operative out of a certain position to establish a motorcircuit, a shunting relay effective when picked-up to shunt the fieldWinding of the motor and when dropped-out to remove the shunt connection from the field Winding, means effective in the said certainposition of the controller for causing pick-up of said relay, means forestablishing a holding circuit for maintaining said shunting relaypicked-up when said controller is initially moved out of its saidcertain position, current-responsive means responsive to the cur rent inthe motor circuit and effective to interrupt said holding circuit tocause drop-out of said -shunting relay when the current in the motorcircuit exceeds a certain value, a motor controln ling resistor in themotor circuit, a stepping relay having a rotary armature effective uponrotation to progressively exclude said resistor from motor circuit, andmeans effective in response to the drop-out of said shunting relay forrendering said current-responsive means effective to control saidstepping relay in a manner to cause it to progressively exclude saidresistor from the motor circuit.

14. In a control system for a motor having a field Winding, thecombination of a controller having a certain position in which a dynamicbraking circuit for the motor is established and operative out of saidcertain position through a plurality of positions in which the dynamicbraking circuit is maintained, a shunting relay efective when picked-upto cause shunting of the field winding of the motor and when dropped-outto cause unshunting of the eld winding, means effective in said certainposition of the controller for causing pick-up of said shunting relay,means for establishing a self-holding circuit for said shunting relay tomaintain said relay picked-up after the controller is shifted out of itssaid certain position, current-responsive means responsive to currentexceeding a certain value in the dynamic braking circuit forinterrupting the selfholding circuit of said shunting relay to therebycause drop-out of the relay, a plurality of fixed resistors and onevariable resistor in the dynamic braking circuit, a reversible steppingrelay having a rotary armature operative to cause progressive exclusionof said variable resistor from the dy namic braking circuit, meansresponsive t0 the drop-out of said shunting relay for rendering saidcurrent-responsive means effective to control the stepping relay in amanner to progressively ex clude said variable resistor from the dynamic.braking circuit, means effective upon operation of the stepping relayin one direction to completely exclude the variable resistor from themotor circuit for cutting one of said xed resistors out of the circuit,for effecting reversal of the stepping relay, and for reconnecting saidvariable resistor in the circuit in such a manner as to be progressivelyexcluded in response to the operation of the stepping relay in thereverse direction, means effective upon the second exclusion of saidvariable resistor from the motor circuit for cutting another of said xedresistors out of thevmotor circuit, for effecting reversed operation ofsaid stepping relay in the said one direction again and for reconnectingsaid variable resistor in the dynamic braking circuit in such a manneras to be again progressively excluded in response to the operation ofthe stepping relay in the said one direction, and means effective uponthe complete exclusion of said variable resistor upon the motor circuitin response to the lastementioned operation of the stepping relay forcausing pick-up of said shunting relay and the consequent shunting ofthe field winding of the motor.

15. In a propulsion and braking control system for a vehicle having oneor more propulsion motors, the combination of means for alternativelyestablishing a propulsion circuit or a dynamic braking circuit for theone or more motors, a resistor connected in either the propulsioncircuit or the dynamic braking circuit, ya stepping relay operative tovary the amount of the resistor included in either the propulsioncircuit or the dynamic brakingcircuit, and means controlled by eitherthe propulsion current or the dynamic braking current for controllingthe operation of said stepping relay.

16. In a propulsion and braking control system for a vehicle having oneor more propulsion motors, the combination of a controller having acoasting position in which a dynamic braking circuit for the one or moremotors is established, said controller being operative different degreesout of said coasting position in one direction into a propulsion zone toestablish a propulsion circuit for the one or more motors and operativedif-

